* return 1 if valid rtt 0 otherwise
*/
static int
-tcp_update_rtt (tcp_connection_t * tc, u32 ack)
+tcp_update_rtt (tcp_connection_t * tc, tcp_rate_sample_t * rs, u32 ack)
{
u32 mrtt = 0;
/* Karn's rule, part 1. Don't use retransmitted segments to estimate
* RTT because they're ambiguous. */
- if (tcp_in_cong_recovery (tc) || tc->sack_sb.sacked_bytes)
+ if (tcp_in_cong_recovery (tc))
{
- if (tcp_in_recovery (tc))
- return 0;
+ /* Accept rtt estimates for samples that have not been retransmitted */
+ if ((tc->flags & TCP_CONN_RATE_SAMPLE) && !(rs->flags & TCP_BTS_IS_RXT))
+ {
+ mrtt = rs->rtt_time * THZ;
+ goto estimate_rtt;
+ }
goto done;
}
mrtt = clib_max (now - tc->rcv_opts.tsecr, 1);
}
+estimate_rtt:
+
/* Ignore dubious measurements */
if (mrtt == 0 || mrtt > TCP_RTT_MAX)
goto done;
* otherwise update. */
tcp_retransmit_timer_update (tc);
- /* If not congested, update pacer based on our new
- * cwnd estimate */
- if (!tcp_in_fastrecovery (tc))
- tcp_connection_tx_pacer_update (tc);
+ /* Update pacer based on our new cwnd estimate */
+ tcp_connection_tx_pacer_update (tc);
}
_vec_len (wrk->pending_deq_acked) = 0;
}
vec_add1 (wrk->pending_deq_acked, tc->c_c_index);
tc->flags |= TCP_CONN_DEQ_PENDING;
}
- tc->burst_acked += tc->bytes_acked + tc->sack_sb.snd_una_adv;
-}
-
-/**
- * Check if duplicate ack as per RFC5681 Sec. 2
- */
-static u8
-tcp_ack_is_dupack (tcp_connection_t * tc, vlib_buffer_t * b, u32 prev_snd_wnd,
- u32 prev_snd_una)
-{
- return ((vnet_buffer (b)->tcp.ack_number == prev_snd_una)
- && seq_gt (tc->snd_nxt, tc->snd_una)
- && (vnet_buffer (b)->tcp.seq_end == vnet_buffer (b)->tcp.seq_number)
- && (prev_snd_wnd == tc->snd_wnd));
-}
-
-/**
- * Checks if ack is a congestion control event.
- */
-static u8
-tcp_ack_is_cc_event (tcp_connection_t * tc, vlib_buffer_t * b,
- u32 prev_snd_wnd, u32 prev_snd_una, u8 * is_dack)
-{
- /* Check if ack is duplicate. Per RFC 6675, ACKs that SACK new data are
- * defined to be 'duplicate' */
- *is_dack = tc->sack_sb.last_sacked_bytes
- || tcp_ack_is_dupack (tc, b, prev_snd_wnd, prev_snd_una);
-
- return ((*is_dack || tcp_in_cong_recovery (tc)) && !tcp_is_lost_fin (tc));
+ tc->burst_acked += tc->bytes_acked;
}
#ifndef CLIB_MARCH_VARIANT
return hole;
}
-#endif /* CLIB_MARCH_VARIANT */
-#ifndef CLIB_MARCH_VARIANT
-static void
-scoreboard_update_bytes (tcp_connection_t * tc, sack_scoreboard_t * sb)
+always_inline void
+scoreboard_update_sacked_rxt (sack_scoreboard_t * sb, u32 start, u32 end,
+ u8 has_rxt)
+{
+ if (!has_rxt || seq_geq (start, sb->high_rxt))
+ return;
+
+ sb->rxt_sacked +=
+ seq_lt (end, sb->high_rxt) ? (end - start) : (sb->high_rxt - start);
+}
+
+always_inline void
+scoreboard_update_bytes (sack_scoreboard_t * sb, u32 ack, u32 snd_mss)
{
sack_scoreboard_hole_t *left, *right;
- u32 bytes = 0, blks = 0;
+ u32 sacked = 0, blks = 0, old_sacked;
+
+ old_sacked = sb->sacked_bytes;
sb->last_lost_bytes = 0;
sb->lost_bytes = 0;
sb->sacked_bytes = 0;
- left = scoreboard_last_hole (sb);
- if (!left)
- return;
- if (seq_gt (sb->high_sacked, left->end))
+ right = scoreboard_last_hole (sb);
+ if (!right)
+ {
+ sb->sacked_bytes = sb->high_sacked - ack;
+ return;
+ }
+
+ if (seq_gt (sb->high_sacked, right->end))
{
- bytes = sb->high_sacked - left->end;
+ sacked = sb->high_sacked - right->end;
blks = 1;
}
- while ((right = left)
- && bytes < (TCP_DUPACK_THRESHOLD - 1) * tc->snd_mss
- && blks < TCP_DUPACK_THRESHOLD
- /* left not updated if above conditions fail */
- && (left = scoreboard_prev_hole (sb, right)))
+ while (sacked < (TCP_DUPACK_THRESHOLD - 1) * snd_mss
+ && blks < TCP_DUPACK_THRESHOLD)
{
- bytes += right->start - left->end;
+ if (right->is_lost)
+ sb->lost_bytes += scoreboard_hole_bytes (right);
+
+ left = scoreboard_prev_hole (sb, right);
+ if (!left)
+ {
+ ASSERT (right->start == ack || sb->is_reneging);
+ sacked += right->start - ack;
+ right = 0;
+ break;
+ }
+
+ sacked += right->start - left->end;
blks++;
+ right = left;
}
- /* left is first lost */
- if (left)
+ /* right is first lost */
+ while (right)
{
- do
+ sb->lost_bytes += scoreboard_hole_bytes (right);
+ sb->last_lost_bytes += right->is_lost ? 0 : (right->end - right->start);
+ right->is_lost = 1;
+ left = scoreboard_prev_hole (sb, right);
+ if (!left)
{
- sb->lost_bytes += scoreboard_hole_bytes (right);
- sb->last_lost_bytes += left->is_lost ? 0 : left->end - left->start;
- left->is_lost = 1;
- left = scoreboard_prev_hole (sb, right);
- if (left)
- bytes += right->start - left->end;
+ ASSERT (right->start == ack || sb->is_reneging);
+ sacked += right->start - ack;
+ break;
}
- while ((right = left));
+ sacked += right->start - left->end;
+ right = left;
}
- sb->sacked_bytes = bytes;
+ sb->sacked_bytes = sacked;
+ sb->last_sacked_bytes = sacked - (old_sacked - sb->last_bytes_delivered);
}
/**
return hole;
}
-#endif /* CLIB_MARCH_VARIANT */
-static void
-scoreboard_init_high_rxt (sack_scoreboard_t * sb, u32 snd_una)
+void
+scoreboard_init_rxt (sack_scoreboard_t * sb, u32 snd_una)
{
sack_scoreboard_hole_t *hole;
hole = scoreboard_first_hole (sb);
sb->rescue_rxt = snd_una - 1;
}
-#ifndef CLIB_MARCH_VARIANT
void
scoreboard_init (sack_scoreboard_t * sb)
{
sb->sacked_bytes = 0;
sb->last_sacked_bytes = 0;
sb->last_bytes_delivered = 0;
- sb->snd_una_adv = 0;
sb->high_sacked = 0;
sb->high_rxt = 0;
sb->lost_bytes = 0;
sb->last_lost_bytes = 0;
sb->cur_rxt_hole = TCP_INVALID_SACK_HOLE_INDEX;
+ sb->is_reneging = 0;
}
+
+void
+scoreboard_clear_reneging (sack_scoreboard_t * sb, u32 start, u32 end)
+{
+ sack_scoreboard_hole_t *last_hole;
+
+ clib_warning ("sack reneging");
+
+ scoreboard_clear (sb);
+ last_hole = scoreboard_insert_hole (sb, TCP_INVALID_SACK_HOLE_INDEX,
+ start, end);
+ last_hole->is_lost = 1;
+ sb->tail = scoreboard_hole_index (sb, last_hole);
+ sb->high_sacked = start;
+ scoreboard_init_rxt (sb, start);
+}
+
#endif /* CLIB_MARCH_VARIANT */
/**
void
tcp_rcv_sacks (tcp_connection_t * tc, u32 ack)
{
- sack_scoreboard_hole_t *hole, *next_hole, *last_hole;
- u32 blk_index = 0, old_sacked_bytes, hole_index;
+ sack_scoreboard_hole_t *hole, *next_hole;
sack_scoreboard_t *sb = &tc->sack_sb;
- sack_block_t *blk, tmp;
- int i, j;
+ sack_block_t *blk, *rcv_sacks;
+ u32 blk_index = 0, i, j;
+ u8 has_rxt;
sb->last_sacked_bytes = 0;
sb->last_bytes_delivered = 0;
- sb->snd_una_adv = 0;
+ sb->rxt_sacked = 0;
if (!tcp_opts_sack (&tc->rcv_opts)
&& sb->head == TCP_INVALID_SACK_HOLE_INDEX)
return;
- old_sacked_bytes = sb->sacked_bytes;
+ has_rxt = tcp_in_cong_recovery (tc);
/* Remove invalid blocks */
blk = tc->rcv_opts.sacks;
/* Add block for cumulative ack */
if (seq_gt (ack, tc->snd_una))
{
- tmp.start = tc->snd_una;
- tmp.end = ack;
- vec_add1 (tc->rcv_opts.sacks, tmp);
+ vec_add2 (tc->rcv_opts.sacks, blk, 1);
+ blk->start = tc->snd_una;
+ blk->end = ack;
}
if (vec_len (tc->rcv_opts.sacks) == 0)
tcp_scoreboard_trace_add (tc, ack);
/* Make sure blocks are ordered */
- for (i = 0; i < vec_len (tc->rcv_opts.sacks); i++)
- for (j = i + 1; j < vec_len (tc->rcv_opts.sacks); j++)
- if (seq_lt (tc->rcv_opts.sacks[j].start, tc->rcv_opts.sacks[i].start))
+ rcv_sacks = tc->rcv_opts.sacks;
+ for (i = 0; i < vec_len (rcv_sacks); i++)
+ for (j = i + 1; j < vec_len (rcv_sacks); j++)
+ if (seq_lt (rcv_sacks[j].start, rcv_sacks[i].start))
{
- tmp = tc->rcv_opts.sacks[i];
- tc->rcv_opts.sacks[i] = tc->rcv_opts.sacks[j];
- tc->rcv_opts.sacks[j] = tmp;
+ sack_block_t tmp = rcv_sacks[i];
+ rcv_sacks[i] = rcv_sacks[j];
+ rcv_sacks[j] = tmp;
}
if (sb->head == TCP_INVALID_SACK_HOLE_INDEX)
{
- /* If no holes, insert the first that covers all outstanding bytes */
- last_hole = scoreboard_insert_hole (sb, TCP_INVALID_SACK_HOLE_INDEX,
- tc->snd_una, tc->snd_nxt);
- sb->tail = scoreboard_hole_index (sb, last_hole);
- tmp = tc->rcv_opts.sacks[vec_len (tc->rcv_opts.sacks) - 1];
- sb->high_sacked = tmp.end;
+ /* Handle reneging as a special case */
+ if (PREDICT_FALSE (sb->is_reneging))
+ {
+ /* No holes, only sacked bytes */
+ if (seq_leq (tc->snd_nxt, sb->high_sacked))
+ {
+ /* No progress made so return */
+ if (seq_leq (ack, tc->snd_una))
+ return;
+
+ /* Update sacked bytes delivered and return */
+ sb->last_bytes_delivered = ack - tc->snd_una;
+ sb->sacked_bytes -= sb->last_bytes_delivered;
+ sb->is_reneging = seq_lt (ack, sb->high_sacked);
+ return;
+ }
+
+ /* New hole above high sacked. Add it and process normally */
+ hole = scoreboard_insert_hole (sb, TCP_INVALID_SACK_HOLE_INDEX,
+ sb->high_sacked, tc->snd_nxt);
+ sb->tail = scoreboard_hole_index (sb, hole);
+ }
+ /* Not reneging and no holes. Insert the first that covers all
+ * outstanding bytes */
+ else
+ {
+ hole = scoreboard_insert_hole (sb, TCP_INVALID_SACK_HOLE_INDEX,
+ tc->snd_una, tc->snd_nxt);
+ sb->tail = scoreboard_hole_index (sb, hole);
+ }
+ sb->high_sacked = rcv_sacks[vec_len (rcv_sacks) - 1].end;
}
else
{
- /* If we have holes but snd_una_max is beyond the last hole, update
- * last hole end */
- tmp = tc->rcv_opts.sacks[vec_len (tc->rcv_opts.sacks) - 1];
- last_hole = scoreboard_last_hole (sb);
- if (seq_gt (tc->snd_nxt, last_hole->end))
+ /* If we have holes but snd_nxt is beyond the last hole, update
+ * last hole end or add new hole after high sacked */
+ hole = scoreboard_last_hole (sb);
+ if (seq_gt (tc->snd_nxt, hole->end))
{
- if (seq_geq (last_hole->start, sb->high_sacked))
+ if (seq_geq (hole->start, sb->high_sacked))
{
- last_hole->end = tc->snd_nxt;
+ hole->end = tc->snd_nxt;
}
/* New hole after high sacked block */
else if (seq_lt (sb->high_sacked, tc->snd_nxt))
tc->snd_nxt);
}
}
+
/* Keep track of max byte sacked for when the last hole
* is acked */
- if (seq_gt (tmp.end, sb->high_sacked))
- sb->high_sacked = tmp.end;
+ sb->high_sacked = seq_max (rcv_sacks[vec_len (rcv_sacks) - 1].end,
+ sb->high_sacked);
}
/* Walk the holes with the SACK blocks */
hole = pool_elt_at_index (sb->holes, sb->head);
- while (hole && blk_index < vec_len (tc->rcv_opts.sacks))
+
+ if (PREDICT_FALSE (sb->is_reneging))
+ sb->last_bytes_delivered += hole->start - tc->snd_una;
+
+ while (hole && blk_index < vec_len (rcv_sacks))
{
- blk = &tc->rcv_opts.sacks[blk_index];
+ blk = &rcv_sacks[blk_index];
if (seq_leq (blk->start, hole->start))
{
/* Block covers hole. Remove hole */
{
next_hole = scoreboard_next_hole (sb, hole);
- /* Byte accounting: snd_una needs to be advanced */
+ /* If covered by ack, compute delivered bytes */
if (blk->end == ack)
{
- if (next_hole)
+ u32 sacked = next_hole ? next_hole->start : sb->high_sacked;
+ if (PREDICT_FALSE (seq_lt (ack, sacked)))
{
- if (seq_lt (ack, next_hole->start))
- sb->snd_una_adv = next_hole->start - ack;
- sb->last_bytes_delivered +=
- next_hole->start - hole->end;
+ sb->last_bytes_delivered += ack - hole->end;
+ sb->is_reneging = 1;
}
else
{
- ASSERT (seq_geq (sb->high_sacked, ack));
- sb->snd_una_adv = sb->high_sacked - ack;
- sb->last_bytes_delivered += sb->high_sacked - hole->end;
+ sb->last_bytes_delivered += sacked - hole->end;
+ sb->is_reneging = 0;
}
}
+ scoreboard_update_sacked_rxt (sb, hole->start, hole->end,
+ has_rxt);
scoreboard_remove_hole (sb, hole);
hole = next_hole;
}
{
if (seq_gt (blk->end, hole->start))
{
+ scoreboard_update_sacked_rxt (sb, hole->start, blk->end,
+ has_rxt);
hole->start = blk->end;
}
blk_index++;
/* Hole must be split */
if (seq_lt (blk->end, hole->end))
{
- hole_index = scoreboard_hole_index (sb, hole);
+ u32 hole_index = scoreboard_hole_index (sb, hole);
next_hole = scoreboard_insert_hole (sb, hole_index, blk->end,
hole->end);
-
/* Pool might've moved */
hole = scoreboard_get_hole (sb, hole_index);
hole->end = blk->start;
+
+ scoreboard_update_sacked_rxt (sb, blk->start, blk->end,
+ has_rxt);
+
blk_index++;
ASSERT (hole->next == scoreboard_hole_index (sb, next_hole));
}
else if (seq_lt (blk->start, hole->end))
{
+ scoreboard_update_sacked_rxt (sb, blk->start, hole->end,
+ has_rxt);
hole->end = blk->start;
}
hole = scoreboard_next_hole (sb, hole);
}
}
- if (pool_elts (sb->holes) == 1)
- {
- hole = scoreboard_first_hole (sb);
- if (hole->start == ack + sb->snd_una_adv && hole->end == tc->snd_nxt)
- scoreboard_remove_hole (sb, hole);
- }
-
- scoreboard_update_bytes (tc, sb);
- sb->last_sacked_bytes = sb->sacked_bytes
- - (old_sacked_bytes - sb->last_bytes_delivered);
+ scoreboard_update_bytes (sb, ack, tc->snd_mss);
ASSERT (sb->last_sacked_bytes <= sb->sacked_bytes || tcp_in_recovery (tc));
ASSERT (sb->sacked_bytes == 0 || tcp_in_recovery (tc)
- || sb->sacked_bytes < tc->snd_nxt - seq_max (tc->snd_una, ack));
+ || sb->sacked_bytes <= tc->snd_nxt - seq_max (tc->snd_una, ack));
ASSERT (sb->last_sacked_bytes + sb->lost_bytes <= tc->snd_nxt
- seq_max (tc->snd_una, ack) || tcp_in_recovery (tc));
ASSERT (sb->head == TCP_INVALID_SACK_HOLE_INDEX || tcp_in_recovery (tc)
- || sb->holes[sb->head].start == ack + sb->snd_una_adv);
+ || sb->is_reneging || sb->holes[sb->head].start == ack);
ASSERT (sb->last_lost_bytes <= sb->lost_bytes);
+ ASSERT ((ack - tc->snd_una) + sb->last_sacked_bytes
+ - sb->last_bytes_delivered >= sb->rxt_sacked);
+ ASSERT ((ack - tc->snd_una) >= tc->sack_sb.last_bytes_delivered
+ || (tc->flags & TCP_CONN_FINSNT));
TCP_EVT (TCP_EVT_CC_SCOREBOARD, tc);
}
}
}
-#ifndef CLIB_MARCH_VARIANT
/**
* Init loss recovery/fast recovery.
*
* Triggered by dup acks as opposed to timer timeout. Note that cwnd is
* updated in @ref tcp_cc_handle_event after fast retransmit
*/
-void
+static void
tcp_cc_init_congestion (tcp_connection_t * tc)
{
tcp_fastrecovery_on (tc);
tc->snd_congestion = tc->snd_nxt;
tc->cwnd_acc_bytes = 0;
tc->snd_rxt_bytes = 0;
+ tc->rxt_delivered = 0;
+ tc->prr_delivered = 0;
+ tc->prr_start = tc->snd_una;
tc->prev_ssthresh = tc->ssthresh;
tc->prev_cwnd = tc->cwnd;
- tc->cc_algo->congestion (tc);
- tc->fr_occurences += 1;
- TCP_EVT (TCP_EVT_CC_EVT, tc, 4);
-}
-#endif /* CLIB_MARCH_VARIANT */
-static void
-tcp_cc_recovery_exit (tcp_connection_t * tc)
-{
- tc->rto_boff = 0;
- tcp_update_rto (tc);
- tc->snd_rxt_ts = 0;
- tc->rtt_ts = 0;
- tcp_recovery_off (tc);
- TCP_EVT (TCP_EVT_CC_EVT, tc, 3);
-}
-
-#ifndef CLIB_MARCH_VARIANT
-void
-tcp_cc_fastrecovery_clear (tcp_connection_t * tc)
-{
- tc->snd_rxt_bytes = 0;
- tc->rcv_dupacks = 0;
- tc->rtt_ts = 0;
+ tc->snd_rxt_ts = tcp_tstamp (tc);
+ tcp_cc_congestion (tc);
- tcp_fastrecovery_off (tc);
- tcp_fastrecovery_first_off (tc);
- tc->flags &= ~TCP_CONN_FRXT_PENDING;
+ /* Post retransmit update cwnd to ssthresh and account for the
+ * three segments that have left the network and should've been
+ * buffered at the receiver XXX */
+ if (!tcp_opts_sack_permitted (&tc->rcv_opts))
+ tc->cwnd += 3 * tc->snd_mss;
- TCP_EVT (TCP_EVT_CC_EVT, tc, 3);
+ tc->fr_occurences += 1;
+ TCP_EVT (TCP_EVT_CC_EVT, tc, 4);
}
-#endif /* CLIB_MARCH_VARIANT */
static void
tcp_cc_congestion_undo (tcp_connection_t * tc)
{
tc->cwnd = tc->prev_cwnd;
tc->ssthresh = tc->prev_ssthresh;
- tc->rcv_dupacks = 0;
- if (tcp_in_recovery (tc))
- {
- tcp_cc_recovery_exit (tc);
- tc->snd_nxt = seq_max (tc->snd_nxt, tc->snd_congestion);
- }
- else if (tcp_in_fastrecovery (tc))
- {
- tcp_cc_fastrecovery_clear (tc);
- }
tcp_cc_undo_recovery (tc);
ASSERT (tc->rto_boff == 0);
TCP_EVT (TCP_EVT_CC_EVT, tc, 5);
}
static inline u8
-tcp_cc_is_spurious_fast_rxt (tcp_connection_t * tc)
+tcp_cc_is_spurious_retransmit (tcp_connection_t * tc)
{
- return (tcp_in_fastrecovery (tc)
- && tc->cwnd > tc->ssthresh + 3 * tc->snd_mss);
+ return (tcp_cc_is_spurious_timeout_rxt (tc));
}
-static u8
-tcp_cc_is_spurious_retransmit (tcp_connection_t * tc)
+static inline u8
+tcp_should_fastrecover_sack (tcp_connection_t * tc)
{
- return (tcp_cc_is_spurious_timeout_rxt (tc)
- || tcp_cc_is_spurious_fast_rxt (tc));
+ return (tc->sack_sb.lost_bytes
+ || ((TCP_DUPACK_THRESHOLD - 1) * tc->snd_mss
+ < tc->sack_sb.sacked_bytes));
+}
+
+static inline u8
+tcp_should_fastrecover (tcp_connection_t * tc, u8 has_sack)
+{
+ if (!has_sack)
+ {
+ /* If of of the two conditions lower hold, reset dupacks because
+ * we're probably after timeout (RFC6582 heuristics).
+ * If Cumulative ack does not cover more than congestion threshold,
+ * and:
+ * 1) The following doesn't hold: The congestion window is greater
+ * than SMSS bytes and the difference between highest_ack
+ * and prev_highest_ack is at most 4*SMSS bytes
+ * 2) Echoed timestamp in the last non-dup ack does not equal the
+ * stored timestamp
+ */
+ if (seq_leq (tc->snd_una, tc->snd_congestion)
+ && ((!(tc->cwnd > tc->snd_mss
+ && tc->bytes_acked <= 4 * tc->snd_mss))
+ || (tc->rcv_opts.tsecr != tc->tsecr_last_ack)))
+ {
+ tc->rcv_dupacks = 0;
+ return 0;
+ }
+ }
+ return ((tc->rcv_dupacks == TCP_DUPACK_THRESHOLD)
+ || tcp_should_fastrecover_sack (tc));
}
static int
tcp_cc_recover (tcp_connection_t * tc)
{
+ sack_scoreboard_hole_t *hole;
+ u8 is_spurious = 0;
+
ASSERT (tcp_in_cong_recovery (tc));
+
if (tcp_cc_is_spurious_retransmit (tc))
{
tcp_cc_congestion_undo (tc);
- return 1;
+ is_spurious = 1;
}
- if (tcp_in_recovery (tc))
- tcp_cc_recovery_exit (tc);
- else if (tcp_in_fastrecovery (tc))
+ tc->rcv_dupacks = 0;
+ tc->prr_delivered = 0;
+ tc->rxt_delivered = 0;
+ tc->snd_rxt_bytes = 0;
+ tc->snd_rxt_ts = 0;
+ tc->rtt_ts = 0;
+ tc->flags &= ~TCP_CONN_RXT_PENDING;
+
+ /* Previous recovery left us congested. Continue sending as part
+ * of the current recovery event with an updated snd_congestion */
+ if (tc->sack_sb.sacked_bytes)
{
- tcp_cc_recovered (tc);
- tcp_cc_fastrecovery_clear (tc);
+ tc->snd_congestion = tc->snd_nxt;
+ tc->snd_rxt_ts = tcp_tstamp (tc);
+ tc->prr_start = tc->snd_una;
+ scoreboard_init_rxt (&tc->sack_sb, tc->snd_una);
+ tcp_program_retransmit (tc);
+ return is_spurious;
}
+ hole = scoreboard_first_hole (&tc->sack_sb);
+ if (hole && hole->start == tc->snd_una && hole->end == tc->snd_nxt)
+ scoreboard_clear (&tc->sack_sb);
+
+ if (!tcp_in_recovery (tc) && !is_spurious)
+ tcp_cc_recovered (tc);
+
+ tcp_connection_tx_pacer_reset (tc, tc->cwnd, 0 /* start bucket */ );
+
+ tcp_fastrecovery_off (tc);
+ tcp_fastrecovery_first_off (tc);
+ tcp_recovery_off (tc);
+ TCP_EVT (TCP_EVT_CC_EVT, tc, 3);
+
ASSERT (tc->rto_boff == 0);
ASSERT (!tcp_in_cong_recovery (tc));
ASSERT (tcp_scoreboard_is_sane_post_recovery (tc));
- return 0;
+ return is_spurious;
}
static void
tc->snd_congestion = tc->snd_una - 1;
}
-static u8
-tcp_should_fastrecover_sack (tcp_connection_t * tc)
-{
- return (TCP_DUPACK_THRESHOLD - 1) * tc->snd_mss < tc->sack_sb.sacked_bytes;
-}
-
-static u8
-tcp_should_fastrecover (tcp_connection_t * tc)
-{
- return (tc->rcv_dupacks == TCP_DUPACK_THRESHOLD
- || tcp_should_fastrecover_sack (tc));
-}
-
/**
* One function to rule them all ... and in the darkness bind them
*/
tcp_cc_handle_event (tcp_connection_t * tc, tcp_rate_sample_t * rs,
u32 is_dack)
{
- u32 rxt_delivered;
+ u8 has_sack = tcp_opts_sack_permitted (&tc->rcv_opts);
- if (tcp_in_fastrecovery (tc) && tcp_opts_sack_permitted (&tc->rcv_opts))
- {
- if (tc->bytes_acked)
- goto partial_ack;
- tcp_program_fastretransmit (tc);
- return;
- }
/*
- * Duplicate ACK. Check if we should enter fast recovery, or if already in
- * it account for the bytes that left the network.
+ * If not in recovery, figure out if we should enter
*/
- else if (is_dack && !tcp_in_recovery (tc))
+ if (!tcp_in_cong_recovery (tc))
{
- TCP_EVT (TCP_EVT_DUPACK_RCVD, tc, 1);
- ASSERT (tc->snd_una != tc->snd_nxt || tc->sack_sb.last_sacked_bytes);
+ ASSERT (is_dack);
tc->rcv_dupacks++;
+ TCP_EVT (TCP_EVT_DUPACK_RCVD, tc, 1);
+ tcp_cc_rcv_cong_ack (tc, TCP_CC_DUPACK, rs);
- /* Pure duplicate ack. If some data got acked, it's handled lower */
- if (tc->rcv_dupacks > TCP_DUPACK_THRESHOLD && !tc->bytes_acked)
+ if (tcp_should_fastrecover (tc, has_sack))
{
- ASSERT (tcp_in_fastrecovery (tc));
- tcp_cc_rcv_cong_ack (tc, TCP_CC_DUPACK, rs);
- return;
- }
- else if (tcp_should_fastrecover (tc))
- {
- u32 pacer_wnd;
-
- ASSERT (!tcp_in_fastrecovery (tc));
-
- /* Heuristic to catch potential late dupacks
- * after fast retransmit exits */
- if (is_dack && tc->snd_una == tc->snd_congestion
- && timestamp_leq (tc->rcv_opts.tsecr, tc->tsecr_last_ack))
- {
- tc->rcv_dupacks = 0;
- return;
- }
-
tcp_cc_init_congestion (tc);
- if (tcp_opts_sack_permitted (&tc->rcv_opts))
- scoreboard_init_high_rxt (&tc->sack_sb, tc->snd_una);
+ if (has_sack)
+ scoreboard_init_rxt (&tc->sack_sb, tc->snd_una);
- /* Constrain rate until we get a partial ack */
- pacer_wnd = clib_max (0.1 * tc->cwnd, 2 * tc->snd_mss);
- tcp_connection_tx_pacer_reset (tc, pacer_wnd,
- 0 /* start bucket */ );
- tcp_program_fastretransmit (tc);
- return;
- }
- else if (!tc->bytes_acked
- || (tc->bytes_acked && !tcp_in_cong_recovery (tc)))
- {
- tcp_cc_rcv_cong_ack (tc, TCP_CC_DUPACK, rs);
- return;
- }
- else
- goto partial_ack;
- }
- /* Don't allow entry in fast recovery if still in recovery, for now */
- else if (0 && is_dack && tcp_in_recovery (tc))
- {
- /* If of of the two conditions lower hold, reset dupacks because
- * we're probably after timeout (RFC6582 heuristics).
- * If Cumulative ack does not cover more than congestion threshold,
- * and:
- * 1) The following doesn't hold: The congestion window is greater
- * than SMSS bytes and the difference between highest_ack
- * and prev_highest_ack is at most 4*SMSS bytes
- * 2) Echoed timestamp in the last non-dup ack does not equal the
- * stored timestamp
- */
- if (seq_leq (tc->snd_una, tc->snd_congestion)
- && ((!(tc->cwnd > tc->snd_mss
- && tc->bytes_acked <= 4 * tc->snd_mss))
- || (tc->rcv_opts.tsecr != tc->tsecr_last_ack)))
- {
- tc->rcv_dupacks = 0;
- return;
+ tcp_connection_tx_pacer_reset (tc, tc->cwnd, 0 /* start bucket */ );
+ tcp_program_retransmit (tc);
}
- }
-
- if (!tc->bytes_acked)
- return;
-partial_ack:
- TCP_EVT (TCP_EVT_CC_PACK, tc);
+ return;
+ }
/*
- * Legitimate ACK. 1) See if we can exit recovery
+ * Already in recovery. See if we can exit and stop retransmitting
*/
- /* Update the pacing rate. For the first partial ack we move from
- * the artificially constrained rate to the one after congestion */
- tcp_connection_tx_pacer_update (tc);
-
if (seq_geq (tc->snd_una, tc->snd_congestion))
{
- tcp_retransmit_timer_update (tc);
-
/* If spurious return, we've already updated everything */
if (tcp_cc_recover (tc))
{
}
/*
- * Legitimate ACK. 2) If PARTIAL ACK try to retransmit
+ * Process (re)transmit feedback. Output path uses this to decide how much
+ * more data to release into the network
*/
-
- /* XXX limit this only to first partial ack? */
- tcp_retransmit_timer_update (tc);
-
- /* RFC6675: If the incoming ACK is a cumulative acknowledgment,
- * reset dupacks to 0. Also needed if in congestion recovery */
- tc->rcv_dupacks = 0;
-
- /* Post RTO timeout don't try anything fancy */
- if (tcp_in_recovery (tc))
+ if (has_sack)
{
- tcp_cc_rcv_ack (tc, rs);
- transport_add_tx_event (&tc->connection);
- return;
- }
+ tc->rxt_delivered += tc->sack_sb.rxt_sacked;
+ tc->prr_delivered += tc->bytes_acked + tc->sack_sb.last_sacked_bytes
+ - tc->sack_sb.last_bytes_delivered;
- /* Remove retransmitted bytes that have been delivered */
- if (tcp_opts_sack_permitted (&tc->rcv_opts))
+ tcp_program_retransmit (tc);
+ }
+ else
{
- ASSERT (tc->bytes_acked + tc->sack_sb.snd_una_adv
- >= tc->sack_sb.last_bytes_delivered
- || (tc->flags & TCP_CONN_FINSNT));
-
- /* If we have sacks and we haven't gotten an ack beyond high_rxt,
- * remove sacked bytes delivered */
- if (seq_lt (tc->snd_una, tc->sack_sb.high_rxt))
+ if (is_dack)
{
- rxt_delivered = tc->bytes_acked + tc->sack_sb.snd_una_adv
- - tc->sack_sb.last_bytes_delivered;
- ASSERT (tc->snd_rxt_bytes >= rxt_delivered);
- tc->snd_rxt_bytes -= rxt_delivered;
+ tc->rcv_dupacks += 1;
+ TCP_EVT (TCP_EVT_DUPACK_RCVD, tc, 1);
}
+ tc->rxt_delivered = clib_max (tc->rxt_delivered + tc->bytes_acked,
+ tc->snd_rxt_bytes);
+ if (is_dack)
+ tc->prr_delivered += 1;
else
- {
- /* Apparently all retransmitted holes have been acked */
- tc->snd_rxt_bytes = 0;
- tc->sack_sb.high_rxt = tc->snd_una;
- }
+ tc->prr_delivered += tc->bytes_acked - tc->snd_mss * tc->rcv_dupacks;
+
+ /* If partial ack, assume that the first un-acked segment was lost */
+ if (tc->bytes_acked || tc->rcv_dupacks == TCP_DUPACK_THRESHOLD)
+ tcp_fastrecovery_first_on (tc);
+
+ tcp_program_retransmit (tc);
}
- else
+
+ /*
+ * Notify cc of the event
+ */
+
+ if (!tc->bytes_acked)
{
- tcp_fastrecovery_first_on (tc);
- if (tc->snd_rxt_bytes > tc->bytes_acked)
- tc->snd_rxt_bytes -= tc->bytes_acked;
- else
- tc->snd_rxt_bytes = 0;
+ tcp_cc_rcv_cong_ack (tc, TCP_CC_DUPACK, rs);
+ return;
}
- tcp_cc_rcv_cong_ack (tc, TCP_CC_PARTIALACK, rs);
+ /* RFC6675: If the incoming ACK is a cumulative acknowledgment,
+ * reset dupacks to 0. Also needed if in congestion recovery */
+ tc->rcv_dupacks = 0;
- /*
- * Since this was a partial ack, try to retransmit some more data
- */
- tcp_program_fastretransmit (tc);
+ if (tcp_in_recovery (tc))
+ tcp_cc_rcv_ack (tc, rs);
+ else
+ tcp_cc_rcv_cong_ack (tc, TCP_CC_PARTIALACK, rs);
+}
+
+/**
+ * Check if duplicate ack as per RFC5681 Sec. 2
+ */
+always_inline u8
+tcp_ack_is_dupack (tcp_connection_t * tc, vlib_buffer_t * b, u32 prev_snd_wnd,
+ u32 prev_snd_una)
+{
+ return ((vnet_buffer (b)->tcp.ack_number == prev_snd_una)
+ && seq_gt (tc->snd_nxt, tc->snd_una)
+ && (vnet_buffer (b)->tcp.seq_end == vnet_buffer (b)->tcp.seq_number)
+ && (prev_snd_wnd == tc->snd_wnd));
+}
+
+/**
+ * Checks if ack is a congestion control event.
+ */
+static u8
+tcp_ack_is_cc_event (tcp_connection_t * tc, vlib_buffer_t * b,
+ u32 prev_snd_wnd, u32 prev_snd_una, u8 * is_dack)
+{
+ /* Check if ack is duplicate. Per RFC 6675, ACKs that SACK new data are
+ * defined to be 'duplicate' as well */
+ *is_dack = tc->sack_sb.last_sacked_bytes
+ || tcp_ack_is_dupack (tc, b, prev_snd_wnd, prev_snd_una);
+
+ /* If reneging, wait for timer based retransmits */
+ if (PREDICT_FALSE (tcp_is_lost_fin (tc) || tc->sack_sb.is_reneging))
+ return 0;
+
+ return (*is_dack || tcp_in_cong_recovery (tc));
}
/**
vnet_buffer (b)->tcp.ack_number,
clib_net_to_host_u16 (th->window) << tc->snd_wscale);
tc->bytes_acked = vnet_buffer (b)->tcp.ack_number - tc->snd_una;
- tc->snd_una = vnet_buffer (b)->tcp.ack_number + tc->sack_sb.snd_una_adv;
+ tc->snd_una = vnet_buffer (b)->tcp.ack_number;
tcp_validate_txf_size (tc, tc->bytes_acked);
+ if (tc->flags & TCP_CONN_RATE_SAMPLE)
+ tcp_bt_sample_delivery_rate (tc, &rs);
+
if (tc->bytes_acked)
{
tcp_program_dequeue (wrk, tc);
- tcp_update_rtt (tc, vnet_buffer (b)->tcp.ack_number);
+ tcp_update_rtt (tc, &rs, vnet_buffer (b)->tcp.ack_number);
}
- if (tc->flags & TCP_CONN_RATE_SAMPLE)
- tcp_bt_sample_delivery_rate (tc, &rs);
-
TCP_EVT (TCP_EVT_ACK_RCVD, tc);
/*
/* Update rtt and rto */
tcp_estimate_initial_rtt (tc0);
+ tcp_connection_tx_pacer_update (tc0);
/* Switch state to ESTABLISHED */
tc0->state = TCP_STATE_ESTABLISHED;
Code Review / vpp.git / blobdiff